Liquid crystal display apparatus

ABSTRACT

In an LCD apparatus ( 400 ) having simplified structure and improved luminance, a light supplying unit ( 100 ) supplies an LCD panel ( 280 ) with red light during a time corresponding to one-third of a frame, green light during the time and blue light during the time. A light reflective-transmissive unit is disposed between the light supplying unit ( 100 ) and the LCD panel assembly ( 200 ) to transmit the red light, the green light and the blue light and to reflect an external light from exterior of the LCD panel assembly ( 200 ). The LCD apparatus displays an image by means of white light as well as red light, green light and blue light, thereby improving luminance and simplifying structure.

TECHNICAL FIELD

The present invention relates to a liquid crystal display (hereinafter,referred to as LCD) apparatus, and more particularly to an LCD apparatushaving a simplified structure and an improved luminance.

BACKGROUND ART

Liquid crystal, generally, varies arrangement in response to an electricfield applied thereto, and thus a light transmittance thereof may bechanged. An LCD apparatus displays an image using the liquid crystal.

A conventional LCD apparatus includes an LCD panel controlling theliquid crystal and a light-supplying unit supplying white light in whichred light, green light and blue light are mixed in an amount equal toeach other.

Also, the conventional LCD apparatus further includes a first substrateand a second substrate opposite to the first substrate.

The first substrate has a plurality of pixels arranged in a matrixshape. Each of the pixels acts as a minimum unit for generating a colorin the LCD apparatus. Each of the pixels includes three subpixels,thereby a light being generated by means of an additive color mixture ofthree primary colors. Each of the subpixels includes a pixel electrodeand a thin film transistor (hereinafter, referred to as TFT). Gray-scalevoltages having voltage levels different from each other are supplied tothe respective subpixels through corresponding TFTs.

The second substrate has a common electrode and a color filter. Thecommon electrode has an area enough to cover all of the pixels formed onthe first substrate. The color filter has an area substantially equal tothe area of the subpixels and is formed at a position corresponding toeach of the subpixels.

Liquid crystal is disposed between the pixels and the common electrode.The liquid crystal varies arrangement in response to a voltagedifference between the gray-scale voltage applied on each of thesubpixels and a voltage applied on the common electrode, therebychanging a light transmittance of the liquid crystal.

The amount of the light having uniform luminance and provided to thefirst substrate may be varied in accordance with a position on which theliquid crystal is disposed while the light passes through the liquidcrystal corresponding to each of the subpixels, thereby forming an imagelight. The image light is changed into a monochrome image light whilepassing through the color filters. The monochrome image light emittedfrom the three subpixels are mixed with each other so as to provide acolor.

When the LCD panel has a diagonal length of about 6.4 inches and aresolution of 640×480, the LCD panel has pixels of about 307,200 andsubpixels of about 921,600.

However, the image light is absorbed into the color filter while passingthrough the liquid crystal and color filter, so that the luminance ofthe monochrome image light may be decreased and image quality of theimage may be deteriorated.

Also, since three subpixels are needed to generate a color, and each ofthe subpixels includes the TFT. As a result, a manufacturing process ofthe LCD panel may be complex, thereby decreasing yield of the LCD panel.

In addition, a driving module for driving the TFTs has a complicatedstructure because the TFTs connected to the subpixels are drivenindividually by means of the driving module.

Furthermore, a black matrix is disposed between the subpixels, on whichthe liquid crystal is not disposed, thereby decreasing an opening ratioand deteriorating luminance of a displayed image on the LCD panel.

DISCLOSURE OF INVENTION Technical Problem

Accordingly, the present invention has been devised to solve theforegoing problems of the conventional art, and the present inventionprovides an LCD apparatus having a simplified structure and an improvedluminance.

Technical Solution

The liquid crystal display (LCD) apparatus according to one aspect ofthe present invention includes an LCD panel assembly, a light supplyingunit, and a light reflective-transmissive unit. The LCD panel assemblyhas a plurality of pixels to display a color image. The pixels controlan arrangement of liquid crystal. The light supplying unit has a lightsource. The light source supplies red light during a time correspondingto one third of a frame, green light during the time and blue lightduring the time. The light reflective-transmissive unit is disposedbetween the light supplying unit and the LCD panel assembly to transmitthe red light, the green light and the blue light and to reflect lightexternally provided to the LCD panel assembly, thereby improvingluminance of the color image.

The LCD apparatus according to another aspect of the present inventionincludes a light supplying unit, a first liquid crystal display part, asecond liquid crystal display part and a light reflective-transmissivefilm.

The light supplying unit includes a light guide plate and a lightsource. The light guide plate has a first light-exiting surface, asecond light-exiting surface and a side surface. The secondlight-exiting surface is opposite to the first light-exiting surface.The side surface is disposed between the first light-exiting surface andthe second light-exiting surface. The light source supplies red lightduring a time corresponding to one third of a frame, green light duringthe time and blue light during the time.

The first liquid crystal display part is opposite to the firstlight-exiting surface, and displays a first image by means of the redlight, the green light and the blue light from the first light-exitingsurface.

The second liquid crystal display part is opposite to the secondlight-exiting surface, and displays a second image by means of the redlight, the green light and the blue light from the second light-exitingsurface.

The light reflective-transmissive film is disposed between the firstliquid crystal display part and the first light-exiting surface totransmit the red light, the green light and the blue light and toreflect light externally provided to the first liquid crystal displaypart.

Therefore, the LCD apparatus of the present invention displays an imageby means of a white light as well as red light, green light and bluelight, thereby improving luminance.

DESCRIPTION OF DRAWINGS

The above and other advantages of the present invention will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic view showing an LCD apparatus according to anexemplary embodiment of the present invention;

FIG. 2 is a cross-sectional view showing the LCD apparatus shown in FIG.1;

FIG. 3 is a schematic view showing the pixel formed on a first substrateshown in FIG. 2

FIG. 4 is a cross-sectional view showing the pixel shown in FIG. 3;

FIG. 5 is a schematic view showing the light-supplying unit shown inFIG. 1;

FIG. 6 is a schematic view showing another light-supplying unit shown inFIG. 1;

FIG. 7 is a schematic view showing another light-supplying unit shown inFIG. 1;

FIG. 8 is a cross-sectional view cut along the line A-A′ of FIG. 7;

FIGS. 9 to 11 are block diagrams showing the driving module shown inFIG. 1;

FIG. 12 is a perspective view showing the light reflective-transmissivefilm shown in FIG. 1;

FIG. 13 is a schematic view showing a TFT substrate of an LCD apparatusaccording to another exemplary embodiment of the present invention;

FIG. 14 is a cross-sectional view showing the LCD apparatus according toanother exemplary embodiment of the present invention; and

FIG. 15 is a schematic view showing an LCD apparatus according toanother exemplary embodiment of the present invention.

BEST MODE

FIG. 1 is a schematic view showing an LCD apparatus 400 according to anexemplary embodiment of the present invention.

Referring to FIG. 1, the LCD apparatus 400 includes an LCD panelassembly 200 without a color filter, a light-supplying unit 100 having alight source and a light reflective-transmissive film 300. The LCDapparatus 400 may include a backlight assembly in lieu of thelight-supplying unit 100.

FIG. 2 is a cross-sectional view showing the LCD apparatus 400 shown inFIG. 1.

Referring to FIG. 2, the LCD panel 280 includes a first substrate 210, asecond substrate 220 and liquid crystal 230.

The first substrate 210 includes a plurality of pixels 212. Each of thepixels 212 acts as a minimum unit for generating a color in the LCDapparatus 400. When the LCD panel 280 has a diagonal length of 6.4inches and a required resolution of 640×480, the LCD panel 280 haspixels of about 307,200.

In this exemplary embodiment, in order to improve luminance and tosimplify structure of the LCD panel 280, each of the pixels 212 of theLCD panel 280 does not include a subpixel.

FIG. 3 is a schematic view showing the pixel formed on a first substrateshown in FIG. 2, and FIG. 4 is a cross-sectional view showing the pixelshown in FIG. 3.

Referring to FIGS. 3 and 4, a number of the pixels 212 are substantiallyequal to the resolution of the LCD panel 280. Each of the pixels 212includes a pixel electrode 213 and a voltage supplying unit 214. Thepixel electrode 213 is formed on the first substrate 210 and has atransparent conductive material, for example, indium tin oxide (ITO) orindium zinc oxide (IZO). The pixel electrode 213 is formed on the firstsubstrate 210 in a thin film shape.

The voltage supplying unit 214 includes a gate bus line 215, a data busline 216 and a thin film transistor (TFT) 217.

The gate bus line 215 has a gate line 215 a and a gate electrode 215 bbranched from the gate line 215 a. The data bus line 216 has a data line216 a and a source electrode 216 b branched from the data line 216 a.

Referring to FIGS. 3 and 4, the TFT 217 includes the gate electrode 215b, an insulating layer 216 a, a channel layer 217 b, the sourceelectrode 216 b and a drain electrode 217 c. The insulating layer 217 ainsulates the gate electrode 215 b from other elements such as thesource electrode 216 b and drain electrode 217 c. The channel layer 217b corresponding to the gate electrode 215 b is armed on the insulatinglayer 217 a. The channel layer 217 b includes an amorphous silicon thinfilm 217 d and an n+ amorphous silicon thin film 217 e. The n+ amorphoussilicon thin film 217 e has two pieces formed on the amorphous siliconthin film 217 d and separated from each other. The source electrode 216b and the drain electrode 216 c are disposed on the two pieces,respectively. The pixel electrode 213 is connected to the drainelectrode 217 c.

Referring to FIG. 2, the second substrate 220 includes a commonelectrode 222 formed over the second substrate 220. The common electrode222 has a transparent conductive material such as ITO, IZO or the like.

In order to maintain a cell gap between the first and second substrates210 and 220, a spacer 233 is disposed between the first substrate 210and the second substrate 220. A sealant 235 is disposed on edges of thefirst substrate 210 and an edge of the second substrate 220 so as toprevent leakage of the liquid crystal 230.

The liquid crystal 230 is formed between the first substrate 210 and thesecond substrate 220 using a vacuum injection process or a droppingprocess.

Referring to FIG. 1, the light-supplying unit 100 provides a red light111, a green light 121 and a blue light 131 to the liquid crystal 230 ofthe LCD panel 280.

FIG. 5 is a schematic view showing the light-supplying unit shown inFIG. 1.

Referring to FIG. 5, the light-supplying unit 100 includes red, greenand blue light-supplying unit 110, 120 130, a voltage supplying module140 and a receiving container 180. The red, green and bluelight-supplying units 110, 120 and 130 generate the red light 111, greenlight 121 and blue light 131, respectively.

The red, green and blue light-supplying units 110, 120 and 130 comprisea cold cathode fluorescent lamp.

The red, green and blue light-supplying units 110, 120 and 130 arealternately disposed and parallel to each other.

Each of the red, green and blue light-supplying units 110, 120 and 130includes a first electrode 101 and a second electrode 102.

The voltage-supplying module 140 includes a first voltage-supplyingmodule 142 and a second voltage-supplying module 144. The firstvoltage-supplying module 142 is connected to the first electrode 101 tosupply a first discharge voltage, and the second voltage-supplyingmodule 144 is connected to the second electrode 102 to supply a seconddischarge voltage. A voltage difference between the first dischargevoltage and the second discharge voltage is enough to transfer anelectron between the first electrode 101 and the second electrode 102.The first voltage supplying module 142 and second voltage supplyingmodule 144 receive the first discharge voltage and second dischargevoltage from an inverter (not shown).

The receiving container 180 receives the red, green, bluelight-supplying units 110, 120 and 130 and the voltage-supplying module140.

FIG. 6 is a schematic view showing another light supplying unit shown inFIG. 1.

Referring to FIG. 6, the light supplying unit 100 includes a receivingcontainer 180, a red light emitting diode 150, a green light emittingdiode 160, a blue light emitting diode 170 and a voltage-supplyingmodule 179.

The red, green and blue light emitting diodes 150, 160 and 170 arearranged in a matrix shape in the receiving container 180.

The voltage-supplying module 179 includes a first signal line 155, asecond signal line 165, a third signal line 175 and a signal-supplyingmodule 177. The first, second and third signal lines 155, 165, and 175are arranged in a matrix shape. The first signal line 155 provides afirst driving voltage V₁ to the red luminescent diode 150, the secondsignal line 165 provides a second driving voltage V₂ to the redluminescent diode 150, and the third signal line 155 provides a thirddriving voltage V₃ to the red luminescent diode 150. The signalsupplying module 177 supplies the first, second and third drivingvoltage V₁, V₂ and V₃ to the first, second and third lines 155, 165 and175, respectively.

The first, second and third driving voltage V₁, V₂ and V₃ may have avoltage level different from each other so that the red light emittingdiode 150, the green light emitting diode 160 and the blue lightemitting diode 170 may have substantially the same luminance.

FIG. 7 is a schematic view showing another light supplying unit shown inFIG. 1, and FIG. 8 is a cross-sectional view cut along the line A-A′ ofFIG. 7.

Referring to FIGS. 1, 7 and 8, a light supplying unit 100 includes alight guide plate 192 and a light-supplying module 195. The light guideplate 192 has a shape substantially identical to an LCD panel 200. Forexample, when the LCD panel 230 has a rectangular shape, the light guideplate 192 may have the rectangular shape.

Referring to FIG. 8, the light guide plate 192 includes a firstlight-exiting surface 192 a, a second light-exiting surface 192 b facingthe first light-exiting surface 192 a and a plurality of side surfaces192 c, 192 d, 192 e and 192 f. The light guide plate 192 may have awedge shape or a flat shape. In this exemplary embodiment, the firstlight-exiting surface 192 a and the second light-exiting surface 192 bare parallel to each other. The light guide plate 192 may also have aplurality of receiving recesses 192 g formed on the side surfaces 192 cand 192 f so as to partially receive the light-supplying module 195.

The light-supplying module 195 is disposed in the receiving recesses 192g. The light-supplying module 195 includes a printed circuit board 196and a light source 197. The 3-color light source 197 includes a redlight emitting diode 197 a, a green light emitting diode 197 b and ablue light emitting diode 197 c. The red, green and blue light emittingdiode 197 a, 197 b and 197 c are disposed on the printed circuit board196 corresponding to the receiving recesses 192 g.

Red light, green light and blue light are incident into the light guideplate 192 so that the red light, the green light and the blue lighthaving a plane light source are generated from the first light-exitingsurface 192 a and the second light-exiting surface 192 b, respectively.As shown in FIG. 8, when the LCD panel 200 is disposed on the firstlight-exiting surface 192 a of the light guide plate 192, a reflectingsurface 198 is disposed on the second light-exiting surface 192 b of thelight guide plate 192, thereby reflecting the red light, the green lightand the blue light to the first light-exiting surface 192 a adjacent tothe LCD panel 200.

FIGS. 9 to 11 are block diagrams showing the driving module shown inFIG. 1.

Referring to FIG. 9, the driving module 290 includes a gate driving part291, a data driving part 292, a driving voltage generating part 293connected to the gate driving part 291, a gray-scale voltage generatingpart 294 connected to the data driving part 292, a light sourcecontrolling part 105 and a signal controlling part 295. The light sourcecontrolling part 105 is connected to the light supplying unit 100 so asto control the light-supplying unit 100. The signal controlling part 295controls the gate driving part 291, data driving part 292, drivingvoltage-generating part 293 and gray-scale voltage generating part 294.

The gate driving part 291 is connected to the gate bus line 215 of theLCD panel 280. The gate driving part 291 supplies a gate-driving signalto each of the gate bus line 215 in response to a control signal fromthe signal controlling part 295. The gate-driving signal includes a gateturn-on signal V_(on) and a gate turn-off signal V_(off). The drivingvoltage generating part 293 generates a common voltage V_(com) to supplythe common voltage V_(com) to a common electrode.

The data driving part 292 is connected to the data bus line 216 of theLCD panel 280. The data driving part 292 supplies a gray-scale voltageto the data bus line 216. The gray scale voltage is generated from thegray-scale voltage generating part 294.

The signal controlling part 295 controls the gate driving part 291, thedata driving part 292, the driving voltage generating part 293 and thegray-scale voltage generating part 294. The signal controlling part 295receives a video signal from an exterior information-processing device296 such as a computer.

The video signal includes various signals such as a first red gray-scalesignal R₁, a first green gray-scale signal G₁, a first blue gray-scalesignal B₁, a vertical synchronizing signal V_(sync), a horizontalsynchronizing signal H_(sync), a main clock signal CLK, a data enablesignal DE and so on.

The signal controlling part 295 converts the first red gray-scale signalR₁, the first green gray-scale signal G₁ and the first blue gray-scalesignal B₁ for an LCD panel into a second red gray-scale signal R₂, asecond green gray-scale signal G₂ and a second blue gray-scale signalB₂, respectively.

Referring to FIG. 9, the signal controlling part 295 supplies the secondred gray-scale signal R₂ to the data driving part 292 during a timecorresponding to one-third of a frame. The data driving part 292receives an analog gray-scale voltage corresponding to the second redgray-scale signal R₂ from the gray-scale voltage generating part 294 andoutputs the analog gray-scale voltage to the data bus line 216.

The gate driving part 291 then supplies a gate turn-on pulse signal tothe first gate bus line 215 in response to a gate control signalgenerated from the signal controlling part 295, thereby turning on allof TFTs connected to the first gate bus line 215.

The signal controlling part 295 repeats the processes aforementionedabove such as output process of the second red gray-scale signal R₂ andoutput process of the gray-scale voltage, during the time correspondingto one-third of the frame to supply the red gray-scale voltage to thepixels.

When the signal controlling part 295 supplies the red gray-scale voltageto the pixels, the signal controlling part 295 supplies red lightturn-on signal LCR₂ to the light source controlling part 105 so as toturn on red light generating unit 110. When the red light generatingunit 110 is turned on, green light generating unit 120 and blue lightgenerating unit 130 are turned off. The liquid crystal corresponding tothe pixels are completely arranged when the signal controlling part 295supplies the red light turn-on signal LCR₂ to the light sourcecontrolling part 105.

Thus, when the frame is 16.6 ms, the red light may be emitted outsidethe LCD panel during red light about 5.5 ms corresponding to one-thirdof the frame.

Referring to FIG. 10, the signal controlling part 295 supplies thesecond green gray-scale signal G₂ to the data driving part 292 duringthe time corresponding to one-third of the frame. The data driving part292 receives the analog gray-scale voltage corresponding to the secondgreen gray-scale signal G₂ and outputs the analog gray-scale voltage tothe data bus line 216.

The date driving part 291 then supplies a gate turn-on pulse signal tothe first gate bus line 215 in response to a gate control signalgenerated from the signal controlling part 295 so as to turn on all ofTFTs connected to the gate bus line 215.

The signal controlling part 295 repeats the processes aforementionedabove such as output process of the second green gray-scale signal G₂and output process of the gray-scale voltage, during the timecorresponding to one-third of the frame to supply the green gray-scalevoltage to the pixels.

When the signal controlling part 295 supplies the green gray-scalevoltage to the pixels, the signal controlling part 295 supplies greenlight turn-on signal LCG₂ to the light source controlling part 105 so asto turn on green light generating unit 120. When the green lightgenerating unit 120 is turned on, red light generating unit 110 and bluelight generating unit 130 are turned off. The liquid crystalcorresponding to the pixels are completely arranged when the signalcontrolling part 295 supplies the green light turn-on signal LCG₂ to thelight source controlling part 105.

Thus, when the frame is 16.6 ms, the green light may be emitted outsidethe LCD panel during red light about 5.5 ms corresponding to one-thirdof the frame.

Referring to FIG. 11, the signal controlling part 295 supplies thesecond blue gray-scale signal B₂ to the data driving part 292 during thetime corresponding to one-third of the frame. The data driving part 292receives the analog gray-scale voltage corresponding to the second bluegray-scale signal B₂ and outputs the analog gray-scale voltage to thedata bus line 216.

The date driving part 291 then supplies a gate turn-on pulse signal tothe first gate bus line 215 in response to a gate control signalgenerated from the signal controlling part 295 so as to turn on all ofTFTs connected to the gate bus line 215.

The signal controlling part 295 repeats the processes aforementionedabove such as output process of the second blue gray-scale signal B₂ andoutput process of the gray-scale voltage, during the time correspondingto one-third of the frame to supply the blue gray-scale voltage to thepixels.

When the signal controlling part 295 supplies the blue gray-scalevoltage to the pixels, the signal controlling part 295 supplies bluelight turn-on signal LCB₂ to the light source controlling part 105 so asto turn on blue light generating unit 130. When the bluelight-generating unit 130 is turned on, red light generating unit 110and green light generating unit 120 are turned off. The liquid crystalcorresponding to the pixels are in a complete arrangement when thesignal controlling part 295 supplies the green light turn-on signal LCB₂to the light source controlling part 105.

Thus, when the frame is 16.6 ms, the blue light may be emitted outsidethe LCD panel during red light about 5.5 ms corresponding to one-thirdof the frame.

Therefore, the red light, the green light and the blue light aresuccessively outputted from the LCD panel during the frame, so that auser may perceive an image by means of a shading effect of the redlight, the green light and the blue light.

Referring to FIG. 1, in order to increase luminance of the LCD panel280, the light reflective-transmissive film 300 is disposed between anLCD panel assembly 280 and a light supplying unit 100.

FIG. 12 is a perspective view showing the light reflective-transmissivefilm shown in FIG. 1.

Referring to FIG. 12, the light reflective-transmissive film 300includes a first layer 310 and a second layer 320.

A refractive index of the first layer 310 of the lightreflective-transmissive film 300 has an anisotropy with respective to anXY-plane, but a refractive index of the second layer 320 of the lightreflective-transmissive film 300 does not have the anisotropy withrespective to the XY-plane. X axis is parallel to an extended directionof the light reflective-transmissive film 300, Y axis is substantiallyparallel to a surface of the light reflective-transmissive film 300 andsubstantially perpendicular to the extended direction, and Z axis issubstantially normal to a surface of the light reflective-transmissivefilm 300.

The light reflective-transmissive film 300 has a different anisotropywith respective to a transmittance and the refractive index according toa polarizing state and a direction of an incident light. For example,three main refractive indexes n_(x), n_(y) and n_(z) of the first layer310 and the second layer 320 are defined by the following expressions 1to 5.n1_(x)=n1_(z)≠n1_(y)   Expression 1n2_(x)=n2_(z)=n2_(y)   Expression 2n1_(x)≠n2_(x)   Expression 3n1_(y)≠n2_(y)   Expression 4|n1_(x) −n2_(x) |<|n1_(y) −n2_(y)|  Expression 5

A refractive index difference between the first layer 310 and the secondlayer 320 in an X-direction is smaller than a refractive indexdifference between the first layer 310 and the second layer 320 in aY-direction. Therefore, with reference to Fresnel's equation, when anon-polarized light is incident into the light reflective-transmissivefilm 300 in a Z-direction, a portion of the non-polarized light parallelto the Y-axis is almost completely reflected by the refractive indexdifference. Also, a portion of the non-polarized light parallel to theX-axis is partially reflected by the refractive index difference, and aremained portion of the non-polarized light parallel to the X-axispasses through the surface of the light reflective-transmissive film300.

Two kinds of high molecular layers are alternately disposed to form adielectric multi-layer of birefringency. One of high molecular layershas a large refractive index, and remained one of high molecular layershas a small refractive index.

For example, in case that the first layer 310 has the larger refractiveindex than that of the second layer 320. A relation of the refractiveindex between the first and second layers 310 and 320 is represented bythe following expression 6.n1_(x)=n1_(z)=1.57, n1_(y)=1.86n2_(x)=n2_(y)=n2_(z)=1.57   Expression 6

According to Fresnel's equation, when refractive indexes of the firstlayer 310 in the X and Z directions are substantially equal torefractive indexes of the second layer 320 in the X and Z directions,and the refractive index of the first layer 310 in the Y-direction isdifferent from the refractive index of the second layer 320 in theY-direction, the portion of the non-polarized light, which is parallelto the Y-axis and incident into the light reflective-transmissive film300 in the Z-direction, is completely reflected, and the remainedportion of the non-polarized light parallel to the X-axis completelypasses through the surface of the light reflective-transmissive film300. As the dielectric multi-layer having the briefringency, a dualbrightness enhancement film (hereinafter, refers to as DBEF)manufactured by 3M company is well known. The DBEF has two kinds oflayers that are alternately disposed. The DBEF haspolyethylenenaphtalate layers and polymethylmethacrylate (hereinafter,refers to as PMMA) layers. The polyethylenenaphtalate layers have highbirefringency, and the PMMA layers have isotropy. Naphthalene has flatstructure so that the naphthalene is easily stacked, and a refractiveindex of the naphthalene in stacked direction is different from arefractive index of the naphthalene in other direction. However, PMMAhas amorphous high molecules to have substantially the same refractiveindex regardless of a direction of PMMA.

In case of the DBEF, a portion of a non-polarized light that is parallelto the Y axis is completely reflected, and a portion of a non-polarizedlight, which is parallel to the Y-axis and incident into the DBEF in theZ-direction, completely passes through the surface of the DBEF. However,in case of the light reflective-transmissive film 300, a portion of anon-polarized light that is parallel to the Y axis is completelyreflected by the larger reflective index difference in the Y direction,but a portion of a non-polarized light, which is parallel to the X-axisand incident into the light reflective-transmissive film 300 in theZ-direction, is partially reflected by the smaller reflective indexdifference in the X direction, and the remained portion of thenon-polarized light that is parallel to the X axis passes through thesurface of the light reflective-transmissive film 300.

Two anisotropic light reflective-transmissive layers may be attached toform the light reflective-transmissive film 300. An anisotropic lightreflective-transmissive layer and an isotropic lightreflective-transmissive layer may also be attached to form the lightreflective-transmissive film 300. The anisotropic lightreflective-transmissive layer has different transmittances and differentrefractive indexes corresponding to polarizing state and polarizingdirection of an incident light.

The light reflective-transmissive film 300 may have integral structureor multi-layered structure having separated layers.

Referring to FIG. 1, the light reflective-transmissive film 300 isdisposed between the light supplying unit 100 and the LCD panel 280 sothat red light 111, green light 121 and blue light 131 pass through thelight reflective-transmissive film 300, which reflects light externallyprovided to the LCD panel 280 in an incident direction. The red light111, the green light 121 and the blue light 131 are generated from thelight supplying unit 100.

The red light 111, the green light 121, the blue light 131 and theexternal light pass through the LCD panel 280 so that a luminance of theexternal light is added to the luminance by the additive color mixtureof the red light 111, the green light 121 and the blue light 131,thereby increasing luminance.

FIG. 13 is a schematic view showing a TFT substrate of an LCD apparatusaccording to another exemplary embodiment of the present invention, andFIG. 14 is a cross-sectional view showing the LCD apparatus according toanother exemplary embodiment of the present invention.

Detailed descriptions of the identical elements are omitted, sinceelements of another exemplary embodiment of the present invention aresubstantially identical to the elements of the above exemplaryembodiment of the present invention except an LCD panel.

Referring to FIGS. 13 and 14, an LCD panel includes a first substrate250, a second substrate 270 and liquid crystal 260.

The first substrate 250 includes a voltage-supplying unit 252, anorganic insulating layer 254 and a first electrode 257.

The voltage-supplying unit 252 of another exemplary embodiment issubstantially identical to the voltage-supplying unit 212 of theexemplary embodiment. The organic insulating layer 254 is formed overthe first substrate 250 to cover TFTs 252 a of the voltage-supplyingunit 252. The organic insulating layer 254 has contact holes, and eachof the contact holes exposes a drain electrode 252 b of the TFT 252 a.

The first electrode 257 is formed on the organic insulating layer 254.The first electrode 257 has a transparent electrode 255 and a reflectiveelectrode 256. The reflective electrode 256 has an opening window 256 a.A number of the transparent electrodes 255 are substantially equal to aresolution of the LCD apparatus. A portion of each of the transparentelectrodes 255 is connected to a drain electrode 252 b of each of theTFTs 252 a.

A reflective electrode 256 is formed on the transparent electrode 255.The transparent electrode is disposed on the organic insulating layer254 in a matrix shape. The reflective electrode 256 includes metalhaving high reflectivity such as aluminum, aluminum alloy, or the like.The reflective electrode 256 includes an opening window 256 a.Three-color light generated from a light-supplying unit 100 passesthrough the liquid crystal 260 by means of the opening window 256 a. Aportion of light externally provided to the LCD panel 280 is reflectedin the opening window 256 to pass through the liquid crystal 260.

The second substrate 270 opposite to the first substrate 250 has acommon electrode 272. The common electrode 272 is formed over the secondsubstrate 270, and has a material such as ITO, IZO, or the like. Theliquid crystal 260 is injected between the first substrate 250 and thesecond substrate 270.

FIG. 15 is a schematic view showing an LCD apparatus according toanother exemplary embodiment of the present invention.

Detailed descriptions of the identical elements are omitted, sinceelements of another exemplary embodiment of the present invention aresubstantially identical to the elements of the exemplary embodiment ofthe present invention except an arrangement of an LCD panel.

Referring to FIG. 15, an LCD apparatus 900 includes a light supplyingunit 500, a light reflective-transmissive film 800, a first display part600 and a second display part 700.

The light supplying unit 500 includes a light guide plate 510 and alight-supplying module 520. The light supplying unit 500 supplies redlight during a time corresponding to one third of a frame, green lightduring the time and blue light during the time to a first exitingsurface 511 of the light guide plate 510 and a second exiting surface512 of the light guide plate 510.

The first display part 600 is opposite to the first light-exitingsurface 511 of the light guide plate 510, and the first display part 600displays an image by means of red light, green light and blue light. Thesecond display part 700 is opposite to the second light-exiting surface512 of the light guide plate 510, and the second display part 700displays an image by means of red light, green light and blue light.

The first display part 600 and the second display part 700 may displaydifferent images from each other by means of different driving signals.Sizes of the first display part 600 and the second display part 700 mayalso be different from each other. Preferably, a first reverse-prismsheet is disposed between the first display part 600 and the firstlight-exiting surface 511, and a second reverse-prism sheet is disposedbetween the second display part 700 and the second light-exiting surface512. The first reverse-prism sheet and the second reverse-prism sheetcontrol luminance and viewing angle.

The light reflective-transmissive film 800 may be disposed between thefirst display part 600 and the light guide plate 510. The red light, thegreen light and the blue light pass through the lightreflective-transmissive film 800, which reflects light externallyprovided to the LCD panel. The external light is incident into the firstdisplay part 600. The first display part 600 displays an image by meansof the red light, the green light, the blue light and the externallight.

The second display part 700 displays an image by means of the red light,the green light and the blue light. The red light, the green light andthe blue light are exited from the second light-exiting surface 512 ofthe light guide plate 500.

The first display part 600 may be a transmissive LCD panel without colorfilter or a reflective-transmissive LCD panel without color filter.

The second display part 700 may be a transmissive LCD panel withoutcolor filter or a reflective-transmissive LCD panel without colorfilter.

INDUSTRIAL APPLICABILITY

As mentioned above, the LCD apparatus of the present invention decreasesloss of a light generated from a light supplying unit of an LCDapparatus, thereby improving luminance of an image exited from the LCDapparatus.

Although the exemplary embodiments of the present invention have beendescribed, it is understood that the present invention should not belimited to these exemplary embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thescope of the present invention as hereinafter claimed.

1. An LCD apparatus comprising: an LCD panel assembly having a pluralityof pixels controlling an arrangement of liquid crystal so as to displaya color image; a light supplying unit having a light source supplying ared light during a time corresponding to one-third of a frame, a greenlight during the time and a blue light during the time; and a lightreflective-transmissive unit disposed between the light supplying unitand the LCD panel assembly so as to transmit the red light, the greenlight and the blue light and to reflect a light externally provided tothe LCD panel assembly in order to improve luminance of the color image.2. The LCD apparatus of claim 1, wherein the pixels comprise atransparent electrode transmitting the red light, the green light andthe blue light.
 3. The LCD apparatus of claim 1, wherein the lightsource comprises a red light supplying unit emitting the red light, agreen light supplying unit emitting the green light and a blue lightsupplying unit emitting the blue light.
 4. The LCD apparatus of claim 3,wherein each of the red light supplying unit, the green light supplyingunit and the blue light supplying unit comprises a cold cathodefluorescent lamp.
 5. The LCD apparatus of claim 3, wherein each of thered light supplying unit, the green light supplying unit and the bluelight supplying unit comprises a light emitting diode.
 6. The LCDapparatus of claim 3, wherein the red light supplying unit, the greenlight supplying unit and the blue light supplying unit are alternatelydisposed.
 7. The LCD apparatus of claim 1, wherein the lightreflective-transmissive unit comprises a light reflective-transmissivefilm including a plurality of first layers and a plurality of secondlayers, the first and second layers have different refractive indexesfrom each other, and the first and second layers are alternatelystacked.
 8. The LCD apparatus of claim 7, wherein the lightreflective-transmissive unit is disposed at a position facing the lightsupplying unit of the LCD panel assembly.
 9. The LCD apparatus of claim1, wherein the pixels comprise; a transparent electrode transmitting thered light, the green light and the blue light; and a reflectiveelectrode disposed on the transparent electrode, the reflectiveelectrode having a contact hole through which a portion of thetransparent electrode is exposed.
 10. The LCD apparatus of claim 1,further comprising a light guide plate including a light-exiting surfacefacing the light supplying unit, a light reflecting surface facing thelight-exiting surface and a side surface connecting the light reflectingsurface to the light-exiting surface, and wherein the light source isdisposed on the side surface of the light guide plate.
 11. An LCDapparatus comprising: a light supplying unit including a light guideplate and a light source, the light guide plate having a firstlight-exiting surface, a second light-exiting surface facing the firstlight-exiting surface and a side surface connecting the first and secondlight-exiting surfaces, the light source supplying a red light during atime corresponding to one-third of a frame, a green light during thetime and a blue light during the time; a first liquid crystal displaypart disposed at a position facing the first light-exiting surface so asto receive the red light, the green light and the blue light from thefirst light-exiting surface and to display a first image; a secondliquid crystal display part disposed at a position facing the secondlight-exiting surface so as to receive the red light, the green lightand the blue light exiting from the second light-exiting surface and todisplay a second image; and a light reflective-transmissive filmdisposed between the first liquid crystal display part and the firstlight-exiting surface so as to transmit the red light, the green lightand the blue light provided to the first liquid crystal display part andto reflect an external light provided from an exterior to the firstliquid crystal display part.
 12. The LCD apparatus of claim 11, whereinthe first liquid crystal display part comprises areflective-transmissive type LCD panel displaying an image using the redlight, the green light, the blue light and the external light.
 13. TheLCD apparatus of claim 11, wherein the first liquid crystal display partcomprises a transmissive type LCD panel displaying an image using thered light, the green light, the blue light and the external light. 14.The LCD apparatus of claim 11, wherein the second liquid crystal displaypart comprises a reflective-transmissive type LCD panel displaying animage using the red light, the green light, the blue light and theexternal light.
 15. The LCD apparatus of claim 11, wherein the secondliquid crystal display part comprises a transmissive type LCD paneldisplaying an image using the red light, the green light, the blue lightand the external light.